Collimator with Variable Hole Area Ratio for Uniform Deposition
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Solution Overview
Problem
Semiconductor device fabrication processes face challenges in achieving uniform thickness of thin layers due to spatial variations in sublimation rates and deposition rates across the substrate, leading to defects like voids and non-uniform thickness profiles.
Innovation Solution
A collimator with a plate having a plurality of holes is used, where the area ratio of each hole increases from the center to the edge, allowing source particles to pass through with increased straightness and adjusting deposition rates to compensate for sublimation rate variations, thereby ensuring uniform thickness across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional deposition method is used, then the deposition process is simple and fast, but the thickness uniformity of the thin layer deteriorates due to spatial variations in sublimation and deposition rates
Solution Approach 1:
The collimator plate features holes with different area ratios distributed across its surface, where the area ratio increases from the center toward the edge. This local variation in hole characteristics compensates for the spatial non-uniformity of sublimation rates, allowing uniform deposition thickness across the substrate despite the inherent radial gradient in the deposition process.
Solution Approach 2:
The invention changes the geometric parameter of the holes (area ratio) as a function of position on the plate. By making the area ratio increase from center to edge, the deposition rate is modulated to counterbalance the sublimation rate variation, achieving uniform thin layer thickness through parameter optimization rather than uniform hole design.
2Manufacturing precision
If the area ratio of holes is increased from center to edge, then spatial variations in deposition rates are compensated, but the manufacturing complexity of the collimator increases
Solution Approach 1:
The collimator plate is designed with locally optimized hole characteristics where the area ratio varies spatially from center to edge. This local differentiation in hole geometry enables precise control over deposition uniformity, with each region of the plate tailored to compensate for the specific sublimation rate conditions at that location.
3Manufacturing precision
If a collimator with varying hole area ratios is used, then thickness uniformity is improved, but the device complexity and fabrication difficulty increase
Solution Approach 1:
The invention implements a systematic variation of the hole area ratio parameter across the plate surface, transitioning from smaller area ratios at the center to larger area ratios at the edges. This controlled parameter change provides a mathematically optimized solution to achieve uniform deposition, transforming a complex uniformity problem into a manageable geometric progression of hole dimensions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The collimator effectively reduces spatial variations in sublimation rates and deposition thickness, resulting in a uniform thin layer thickness across the substrate, minimizing defects like voids and improving overall fabrication quality.
Implementation Method 1
a plasma electrode provided in an upper region of the chamber and configured to generate plasma near the target and thereby to produce particles from the source
Implementation Method 2
a target provided over the heater chuck, the target containing a source for a thin layer to be deposited on the substrate
Implementation Method 3
a heater chuck provided in a lower region of the chamber and configured to heat a substrate
Data Source
AI summary
Disclosed are a collimator, a fabrication apparatus including the same, and a method of fabricating a semiconductor device using the same. The fabrication apparatus may include a chamber, a heater chuck provided in a lower region of the chamber and configured to heat a substrate, a target provided over the heater chuck, the target containing a source for a thin layer to be deposited on the substrate, a plasma electrode provided in an upper region of the chamber and configured to generate plasma near the target and thereby to produce particles from the source, and a collimator provided between the heater chuck and the target.